The lentil (Lens culinaris) is an edible pulse. It is a bushy annual plant of the legume family, known for its lens-shaped seeds. It is about 40 cm (16 in) tall, and the seeds grow in pods, usually with two seeds in each.

The seeds require a cooking time of 10 to 40 minutes, depending on the variety—shorter for small varieties with the husk removed, such as the common red lentil — and have a distinctive, earthy flavor. Lentil recipes[2] are used throughout South Asia, the Mediterranean regions and West Asia. They are frequently combined with rice, which has a similar cooking time. A lentil and rice dish is referred to in western Asia as mujaddara or mejadra. Rice and lentils are also cooked together in khichdi, a popular dish in the Indian subcontinent (India and Pakistan); a similar dish, kushari, made in Egypt, is considered one of two national dishes. Lentils are used to prepare an inexpensive and nutritious soup all over Europe and North and South America, sometimes combined with some form of chicken or pork.

Dried lentils can also be sprouted by soaking in water for one day and keeping moist for several days, which changes their nutrition profile.

Lentils with husk remain whole with moderate cooking; lentils without husk tend to disintegrate into a thick purée, which leads to quite different dishes.[3]

With 26% of total food content from protein (table), lentils have the third-highest level of protein, by weight, of any legume or nut, after soybeans and hemp.[citation needed] Red (or pink) lentils contain a lower concentration of fiber than green lentils (11% versus 31%).[5]

The low levels of readily digestible starch (5%), and high levels of slowly digested starch (30%), make lentils of potential value to people with diabetes.[6] The remaining 65% of the starch is a resistant starch classified as RS1,[7] as a high-content resistant starch, which is 32% amylose. A minimum of 10% in starch from lentils escapes digestion and absorption in the small intestine (therefore called "resistant starch").[8]

Lentils are relatively tolerant to drought, and are grown throughout the world. FAOSTAT reported that the world production of lentils for calendar year 2013 was 4,975,621 metric tons, primarily coming from Canada, India and Turkey.[10]

About a quarter of the worldwide production of lentils is from India, most of which is consumed in the domestic market. Canada is the largest export producer of lentils in the world, and Saskatchewan is the most important producing region in Canada (growing 99% of Canadian lentils).[11]Statistics Canada estimates that Canadian lentil production for the 2009/10 year was a record 1.5 million metric tons.[12] The most commonly grown type is the Laird lentil.[11]

The lens (double-convex shaped) is called as such because an optical lens is similar in shape to the lentil. Lens is the Latin name for lentil.

In Jewish mourning tradition, lentils are traditional as food for mourners, together with boiled eggs, because their round shape symbolizes the life cycle from birth to death.

Lentils were a chief part of the diet of ancient Iranians, who consumed lentils daily in the form of a stew poured over rice.

Lentils are also commonly used in Ethiopia in a stew-like dish called kik, or kik wot, one of the dishes people eat with Ethiopia's national food, injera flat bread. Yellow lentils are used to make a non-spicy stew, which is one of the first solid foods Ethiopian women feed their babies.

In Indian Subcontinent, Dhal or lentil curry is part of everyday diet which is eaten with both rice and roti. Boiled lentil & lentil stock are used as thickening agent in most vegetarian curries. They are also used as stuffing in Dal Parathas & Puris. Lentils are also used in many regional varieties of sweets. It is considered to be one of the best foods because the internal chemical structures are not altered by cooking.

In Italy and Hungary, eating lentils on New Year's Eve traditionally symbolizes the hope for a prosperous new year, most likely because of their round, coin-like form.